Thermal Inactivation of Escherichia coli O157:H7 in Blade-Tenderized Beef Steaks Cooked on a Commercial Open-Flame Gas Grill

Abstract

Beef subprimals were inoculated on the lean side with ca. 4.0 log CFU/g of a cocktail of rifampin-resistant (Rif(r)) Escherichia coli O157:H7 strains and then passed once through a mechanical blade tenderizer with the lean side facing upward. Inoculated subprimals that were not tenderized served as controls. Two core samples were removed from each of three tenderized subprimals and cut into six consecutive segments starting from the inoculated side. A total of six cores were also obtained from control subprimals, but only segment 1 (topmost) was sampled. Levels of E. coli O157:H7 recovered from segment 1 were 3.81 log CFU/g for the control subprimals and 3.36 log CFU/g for tenderized subprimals. The percentage of cells recovered in segment 2 was ca. 25-fold lower than levels recovered from segment 1, but E. coli O157:H7 was recovered from all six segments of the cores obtained from tenderized subprimals. In phase II, lean-side-inoculated (ca. 4.0 log CFU/g), single-pass tenderized subprimals were cut into steaks of various thicknesses (1.91 cm [0.75 in.], 2.54 cm [1.0 in.], and 3.18 cm [1.25 in.]) that were subsequently cooked on a commercial open-flame gas grill to internal temperatures of 48.8 degrees C (120 degrees F), 54.4 degrees C (130 degrees F), and 60 degrees C (140 degrees F). In general, regardless of temperature or thickness, we observed about a 2.6- to 4.2-log CFU/g reduction in pathogen levels following cooking. These data validate that cooking on a commercial gas grill is effective at eliminating relatively low levels of the pathogen that may be distributed throughout a blade-tenderized steak.

Effects of Sodium Citrate plus Sodium Diacetate and Buffered Vinegar on Escherichia coli O157:H7 and Psychrotrophic Bacteria in Brine-Injected Beef

“…In addition, Gill and McGinnis (5) cooked retail whole muscle, nonintact beef from 63 to 68uC and reported that cooking whole muscle, nonintact beef to medium rare would be adequate for reducing aerobic bacteria. Similarly, Luchansky et al (10), using a commercial gas grill to cook E. coli O157:H7inoculated whole muscle, nonintact beef steaks, reported a 2.6 to 4.2 log CFU/g reduction when the meat was cooked between 48.9 and 60uC. The current study supports that cooking brine-injected roast beef to 60uC with a 12-min hold under commercial conditions is an effective method for eliminating internalized E. coli O157:H7.…”

“…Little research has been conducted to streamline this process by examining the efficacy of including antimicrobials directly in the brine solution (11,19,20). Furthermore, thermal processing has been proven to be an effective method of reducing or eliminating internalized pathogens in whole muscle, nonintact beef in experimental settings (10,13). However, the thermal destruction of internalized pathogens needs to be evaluated under simulated commercial conditions for roast beef products.…”

A simplified method for numerical simulation of gas grilling of non-intact beef steaks to eliminate Escherichia coli O157:H7

“…A commercial gas grill (Model XXE-4, Baker's Pride, New Rochelle, NY) was used in this study (Luchansky et al, 2009). Upon use, the gas grill was ignited and the oven was turned on for at least 10 min to allow the flame to stabilize.…”

A comparison of needle-free and needle-injection methods and solutions for enhancement of beef longissimus lumborum muscles

“…However, with this improvement in tenderness, there is a chance that bacteria present on the meat's surface can be transferred to the interior during these processes (Sporing, 1999;Phebus et al, 2000;Sutterfield, 2008). Luchansky et al (2009) concluded that bacterial translocation resulting from blade tenderization occurs primarily in the top portion of the meat, and it is not a food safety concern if the meat is cooked to at least a rare degree of doneness.…”